The invention relates to electric lamps and particularly to electric discharge lamps. More particularly the invention is concerned with a sealing electrode for an electric discharge lamp.
Sealed beam headlamps used to be made with glass reflectors and lens. A filament, or a lamp capsule was enclosed in the interior, and electrically coupled to the exterior by two seals. Each seal was made with hole formed in the glass wall, and a little metal cup was pressed into the glass along the rim of the cup extending around the hole. A metal lead was then extended through the formed hole and attached to the bottom wall of the cup. An electrical connection could then be made to the exterior of the cup, thereby providing electric power through the metal cup to the enclosed filament.
A sealing electrode for a discharge lamp may be made with an electrically conductive cup having a circumferential wall having an interior surface defining an interior volume, and having a sealing portion formed on the cup, extending circumferentially around the cup. An emitter pellet is supported by the cup from at least a portion of the interior surface, the emitter pellet being electrically coupled to the cup. The cup is used to seal an entrance into the discharge lamp volume, while at the same time supporting the emitter acting as the discharge electrode.